PEX For Shop Air Lines?

Have you thought of putting in an in-line moisture filter/trap?

I thought about, but I'm trying figure out if one is really needed.

People don't use a moisture trap when they haul their portable compressors to job sites and use the e.g. 20' black hose that came with compressor, do they? When is a moisture trap needed?

If needed, what price-point would I be looking at for a 150 PSI compressor? I'm not trying to build an industrial strength system, just something for a small shop. Occasional nail gun use, nozzles for clean up, tire fills, etc.

I drain the large tank in my wood shop, regularly, and especially when spra ying finishes.

I've never had a moisture issue with my smaller portable tanks (upholstery shop), I have 2, nor in the hoses. As to your nail/staple guns, oil them r egularly.... that should be sufficient to prevent any moisture issues with them. I've had one small tank for about 5 yrs and the other about 2 yrs. There are no moisture traps on the small tanks, as there is on the large w ood shop tank.

I've occasionally used a small tank for spraying a finish, with no moisture issues, yet. *Sidenote: I suspect the regulators on the Harbor Freight sm all compressors are not accurate, re, spraying requiring a certain pressure (about 40 psi). I regulate to about 50 psi for my best results with my sp ray equipment on these small tanks. Your results may vary.

I wasn't aware the type of moisture trap has a psi rating or requirement. It's the tool rating (maximum) that's important, as for as I know.

Sonny

A moisture trap is needed when moisture sprays out the end of the house into your tool. All of the moisture is from the moist/humid air outside of your compressor being sucked in, heated, and going into a cool tank. The moisture from the air will condense inside the compressor. If you run the compressor enough to begin heating up the compressed air in the tank you will begin to see the moisture being blown out of the end of the hose.

Moisture separators are CHEAP, just add one near the compressor but before you airline.

OR leave the compressor drain line open so that it constantly leaks a little bit, enough to keep up with the condensation that forms inside the tank.

With that said, is PEX going to be adequate for high pressure air?

Just to add a little more, the more air you move through the compressor in a relative short amount of time will determine if you will have a moisture issue.

If you are using a nail gun occasionally you should have no problem Nail guns are high pressure and very low volume users. Your compressor will not be running constantly.

On the other hand, filling a flat automobile tire or blowing your shop out for clean up is a very high volume operation and will promote moisture issues more quickly.

The longer it takes for you to use enough air to trigger a recharge of pressure the better. The hotter the compressor runs the more moisture will be extracted from the air.

If is is raining outside, when running the compressor, or if you live in a humid environment you will more likely have to deal with moisture.

just put one of these on your compressor and be done with the wonderment of it all.

$5.99

On 12/26/2018 2:56 PM, Leon wrote: ...

See ASTM F877 for PEX tubing.

Most box store PEX tubing will be rated 160 psi at 73°F but drops to 100 psi @ 180°F.

It's a little close on rating in my book at 150, but more than likely there's some safety factor in play but I don't have any specifics in that regards.

Thanks for the info, but...

That separator is rated with a working pressure of 90 psi. While I don't usually run at anything more than that, my regulator goes up to the max of the compressor's range (150 psi) which makes running it at the max possible.

Wouldn't shrapnel be a concern? "Weakest link" and all that, if you know what I mean.

That might work if the drain was on the bottom of the compressor. That is not the case with the very common Porter Cable 6 gallon pancake model. Not only is the drain located up the curved side of the tank a few inches, they neglected to center it between 2 of the 3 legs. You have to tilt the unit up onto one leg and then balance it at a specific angle to get it to drain.

It would take some type of angled stand to position the unit so that drain was always at the lowest point. Any idea of these things would mind running at an angle? Overall vibration could be dealt with via some secure strapping, but I wonder about the connection points of the compressor unit at the tank. Hanging/running at a weird angle may not have been designed into the unit.

Home Depot PEX is rated at 160 psi. That's higher than the max the compressor can put out. I don't think I'm concerned about that.

Not buying that science. ;-) The moisture is a constant given the total volume of air. It doesn't matter if it's used slowly or quickly, the moisture is the same. As the air in the tank expands it will cool the same amount[*], no matter what the temperature of the tank is and leave the water behind. The moisture that was pumped into the tank has to come out of the tank somehow. [*] Well, freezing may change things. ;-)

More water in = more water out

That works but it won't keep your tank from becoming a rocket. ;-)

Isn't PEX used in water lines? Water is only an issue for your tools, which generally require a few drops of oil to keep running, and prevent rust. Painting obviously requires an oil and water free environment. Virtually everyone that paints and has a larger, non portable compressor has an oil/water separator in the line. They are cheap, so no reason at all not to get one. You need a pressure regulator anyway, so get one with a filter on it.

I know the stuff is pretty good, and can expand IIRC up to 10%. My house pressurized plumbing is all PEX. I was just wondering if PEX, besides having enough pressure resistance, would pose any other danger like the PVC stories you hear about. It being relatively pliable I would imagine it would simply fail but not fly apart into pieces.

Ah, got'cha. Leave it to PC to add a drain but not one that works like it should. It would probably cost and extra dollar or so, during manufacture, to add a small tube to the inside of the drain valve that reaches down to the bottom of the tank.

If it is oilless it should not matter. If it uses oil as a lube there could be complications if run at an angle. Most of the time construction guys just have them sitting around on an uneven surface but probably not at the angle necessary to keep thank drained.

I was not really paying attention to the PSI, HF sells better ones and I will assume they will handle 150 psi, maybe not. But the better ones are still pretty inexpensive. And then you don't have to be concerned about water getting into your tools.

I will say that I have a 20+ year old 20 gallon compressor with 50' of rubber hose. And I live relatively near the gulf coast in Houston. In the past when I blew out my garage and the compressor cycled on 5~6 times and ran longer than normal I would see water coming out the end of the hose. I have a water separator bolted to the compressor and the hose attaches to the separator.

Yes I would fear that or seals may just fail and it would leak substantially. You would certainly want one rated for the pressure you would be using.

Yeah I did not say that right. ;~) BUT I have found that the larger and the less often the compressor runs the less condensed moisture you find coming out the end of the hose. True the moisture comes out but under ideal conditions it comes out of the drain valve at the bottom of the compressor. A hot compressor tank vaporizes the water inside and it condenses as it comes out the hose. If the compressor stays relatively cool the water tends to stay in the bottom of the tank.

But again you hope the water goes out through the drain exit point.

???

PEX is flexible plastic pipe. It is not used "in" lines, it _is_ the line.

"PEX AL PEX", per ASTM Standard F1281, is intended for use with air and other gases. Check with the manufacturer of the tubing for the pressure rating. I don't know of any PEX that is is rated for UV resistance so be careful with exposure to sunlight or fluorescent lights.

Note that PEX AL PEX uses different fittings from regular PEX. Most of them are similar in design to the compression fittings sold for use with copper, where there is a nut that is tightened down to secure a compression ring.

It is also stiffer and is not usually a Home Depot item--there are many sources online though.

Actual risk involved in using ordinary Home Depot PEX should be small, the result of failure should be the same as failure of a hose, since that's pretty much what it is. Just be sure to secure it in such a manner that a long piece with a fitting on it can't flail around.

With regard to the water issue, with rigid pipe you can design the system so that it slopes to a low point where you can put a drain and periodically drain any water out.

PEX, being flexible, tends to sag a little bit between attachment points so getting it to drain cleanly may be difficult--this is less of a problem with PEX AL PEX as it is stiffer than regular PEX and if you're careful you should be able to get it straight enough to drain.

I was going to say, CPVC is used for water too but definitely _NOT_ advised for air. Personally, I wouldn't use either.

Did you actually think that I was concerned about the PEX getting wet? Wow!

Of course I was concerned about the tools. I specifically mentioned a "tool" as the issue of concern.

Likely not PC but the chinese sweat-shop that builds the darn things. PC just puts their labels on them, and they are too cheap to either do proper quality control or to buy a slightly higher priced unit.

And too cheap to actually engineer a proper one for the Chinese re-education camps to make.